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24
JCAD JOURNAL OF CLINICAL AND AESTHETIC DERMATOLOGY February 2018 • Volume 11 • Number 2
R E V I E W
Cryotherapy produced clearance in 10 lesions after
one treatment, with the remaining 10 lesions
requiring two or three additional treatments.
PDT resulted in clearance of 15 lesions after one
treatment and the remaining five lesions after a
second treatment. The probability that a lesion
cleared after one treatment was significantly
greater with PDT (p<0.01). Cryotherapy was
associated with ulceration (n=5), infection (n=2)
and recurrent disease (n=20). No adverse events
were associated with the use of PDT.
Another controlled study assessed the relative
efficacy of red and green light for the treatment
of Bowen's disease.
27
Four hours following the
application of 20% ALA, lesions were exposed
to red 630±15nm (125J/cm
2
) (n=32) or green
540±15nm (62.5J/cm
2
) (n=29) light. The initial
clearance rate for lesions treated by red light was
94 percent versus 72 percent (21 of 29) for green
light (p=0.002). Over the following 12 months,
there were two recurrences in the red light group
and seven in the green light group, reducing
the overall clearance rates to 88 percent and 48
percent, respectively.
Based on these results, an open-label study
assessed the efficacy of PDT using 630±15nm
(100J/cm
2
) to treat Bowen's disease consisting of
40 large lesions greater than 20mm in diameter
and 45 multiple lesions.
28
ALA was used as the
photosensitizer. Among the large lesions, 35
(88%) cleared after 1 to 3 treatments. Five lesions
failed to clear but all showed partial response.
Among the multiple lesions, 44 (98%) cleared
following one or two treatments; however, four
lesions cleared after 12 months, reducing the
clearance rate to 89%.
Basal cell carcinoma. Despite the success of PDT
using ALA for Bowen's disease, superficial basal
cell carcinoma of the skin (BCC) often respond
poorly. The results of several studies report relapse
rates of 50 percent or greater.
29–31
The objective of
this open-label study was to determine whether
a second PDT treatment after seven days could
improve outcomes. One hour following the
application of 20% ALA, six subjects with 26 BCC
lesions were treated with 630±15nm red light
(120–134J/cm
2
; 50±100mW/cm
2
). The treatment
was repeated after seven days. A complete
response rate of 100 percent was observed one
month after treatment. During a median follow-
up of 27 months (range, 15–45 months), relapse
of one lesion occurred after 16 months. Cosmetic
results were excellent.
Actinic keratosis (AK). AK refers to rough, scaly
lesions that can occur following long-term sun
exposure in fair-skinned individuals. Consequently,
they most often occur on the face, forearms,
and back of the hands.
32
AKs are precancerous
and might eventually progress to squamous cell
carcinoma if left untreated.
21
PDT provides good
cure rates and excellent cosmetic outcomes when
used for the treatment of AK.
21,33
Our review found
that when PDT was used with 20% ALA cream
or solution, long-term cure rates were reported
to be 78 to 89 percent using blue light and 85 to
89 percent using red light.
21
The following trial
described the efficacy of PDT for the treatment of
AK.
Initially, human epidermal keratinocytes were
incubated for 24 hours with ALA ranging from 100
to 500µmol/L and irradiated using 633nm light
(3 to 24J/cm
2
).
34
Cell viability was significantly
reduced. Maximal cytotoxic effects were achieved
using a light dose of 24J/cm
2
. Subsequently, a
clinical ALA-PDT study was performed on 40
subjects with 294 AK lesions.
34
Subjects were
included only if they showed a lesion distribution
suitable for a two-sided comparison. Most lesions
(81%) were located on the face or scalp, 15 percent
were located on the hands, and four percent were
located on the limbs. The treatment groups were
very similar with respect to number of lesions
and lesion grades. ALA 20% in a cream base was
applied to each lesion and 5mm of surrounding
normal tissue. After a four-hour incubation period,
subjects were treated with 633nm light (40J/
cm
2
). Immediately following treatment, subjects
scored pain severity using an 11-point (0–10)
scale. Subjects were evaluated after six, 12, and
24 weeks.
The overall six- and 24-week complete
response rates were 84.3 percent and 38.8 percent,
respectively.
34
All treated lesions developed
erythema and crusting 2 to 4 days after treatment,
FIGURE 3. The effectiveness of phototherapy for the treatment demodex folliculitis is clearly evident in this patient before
(left) and after 7 weekly treatment sessions with a red light=emitting diode (right). Images courtesy of the author.
TABLE 3. Mean efficacy ratings
RATING RETROSPECTIVE N (%) PROSPECTIVE UNTREATED N (%) PROSPECTIVE TREATED N (%)
3 MONTHS
Very Good 17 (61) 18 (64) 19 (68)
Good 7 (25) 6 (22) 7 (25)
Fair 4 (14) 4 (14) 2 (7)
6 MONTHS
Very Good 19 (68) 20 (72) 21 (75)
Good 8 (29) 7 (25) 7 (25)
Fair 1 (3) 1 (3) 0 (0)
From Trelles et al 2006
14